The objectives of the research described in this application are to study the roles of the homotypical neocortex in some of the higher functions of the brain; namely, the visual functions of the parietal lobe system, and particularly its role in certain aspects of visual spatial perception; and, the controlling influence of the behavioral state of directed visual attention upon the functional properties of visual neurons of the parietal lobe and the extrastriate areas of the occipital lobe. Experiments will be made in waking behaving monkeys trained to execute tasks requiring varying degrees of visual attention while, simultaneously, recordings are made of the action potentials of neurons in either the pariental or extrastriate cortical areas, activated by appropriate visual stimuli. The observations will be analyzed for statistical significance, and the results of the studies of single neurons synthesized in terms of the actions of large populations of neurons. The results obtained will be used to make inferences and draw conclusions concerning the role of the parietal lobe system in visual spatial perception, and of the controlling effect of behavioral state upon the mechanisms of the homotypical cortex and its linked distributed systems in the higher functions of the brain.